Manage your subscription

Bipolar teens see hostility in neutral faces

Teens diagnosed with the bipolar disorder are more likely to interpret neutral facial expressions as hostile and react with fear, a new study shows.

Brain scans also showed that the brain centre that processes fear – the amygdala – shows more activity in these youngsters than in those free of the disorder. The researchers say the findings provide insight into how bipolar individuals process emotions differently to their peers.

Bipolar disorder affects about 5.7 million American adults, and is one of the most common psychiatric disorders diagnosed among children. It is characterised by moods that swing between manic highs’ and serious depression.

Melissa DelBello, who researches mood disorders at the University of Cincinnati College of Medicine in Ohio, US, says adolescents with bipolar disorder may have a suicidal reaction to something as simple as a friend not calling them back on the phone. She adds that patients with the disorder also show inappropriate reactions during their manic phases&colon; “A teacher will be yelling at them and they might think this is the funniest thing.”

Advertisement

Face values

In the past, scientists have found that the amygdala, which processes fear and anxiety in the brain, is smaller in young adults with bipolar disorder. “But we didn’t know whether this structural abnormality translates into a functional abnormality,” says DelBello.

Now Ellen Leibenluft of the National Institute of Mental Health in Maryland, US, and colleagues have looked at brain activity in bipolar teenagers using functional magnetic resonance imaging (fMRI) technology. The group also assessed the youngsters’ reactions to a range of faces using targeted questions.

Twenty-two youngsters with bipolar disorder, averaging 14 years in age, were matched with 21 healthy counterparts. All participants reacted similarly to images of happy and fearful faces.

Hostile bias

But the patients with bipolar disorder were more likely to interpret neutral facial expressions as hostile and feel more fearful of these faces. On a scale of 1 to 5, with 5 being most fearful, those with the psychiatric condition gave an average rating of 2 while others gave an average rating of 1.4.

But when asked to assess how wide the noses of the faces were on a scale of 1 to 5 – an assessment not involving emotions – there was no significant difference between groups’ ratings.

The brain scans echoed these findings, with teenagers with bipolar disorder showing more activity in the amygdala in response to neutral faces than the control children. And there was no marked difference in brain activity between the groups when the children were assessing nose widths.

Medication or illness?

The team suggest the current findings in youngsters are important because they presumably come from an early stage of the illness. This, they say, helps to support the idea that amygdala abnormalities could be a cause of the disorder.

But they note that 82% of the bipolar adolescents involved in the study took medication for their condition. These drugs, psychiatrists say, could have somehow contributed to the abnormal fear response among the bipolar individuals. “Nobody knows if this is a medication effect or an illness effect,” DelBello notes.

Leibenluft says that the greater activity in the amygdala in bipolar patients may have something to do with the fact that this region of their brains is smaller than in other people. The amygdala in these patients may be working harder to compensative for its smaller size, she says.

Journal reference&colon; Proceedings of the National Academy of Sciences (DOI&colon; 10.1073/pnas.0603246103)